Hydraulically snubbed truck

ABSTRACT

A hydraulic snubber device for railroad car trucks and more particularly a hydraulic snubber of an improved configuration which is disposed intermediate a bolster and side frame and which includes a circumferential reservoir outside the piston stroke area thereby permitting a minimum height snubber for a given useful stroke.

United States Patent Wagner et al. [4 Mar. 4, 1975 [54] HYDRAULICALLYSNUBBED TRUCK 2,256,868 9/1941 Perkins l05/l97 DH 3,464,366 9/1969 Seay105/197 DH [75] mentors- W Bladfordwoodsy 3,595,350 7/1971 Wl8b8.....105/197 DH x 1301mm wlebe, Sewwkley. both of 3,626,864 12/1971 Wiebe105/197 DH X [73] Assignee: A. Stucki Company, Pittsburgh, Pa. PrimaryExaminer-M. Henson Wood, .lr.

Assistant Examiner-Howard Beltran [22] Flled' 1973 Attorney, Agent, orFirmHoward E. Sandler [21] Appl. No.1 355,058

[57] ABSTRACT [52] Cl 522 A hydraulic snubber device for railroad cartrucks and 51 I t Cl B6 5/12 6 5/50 lqf 9/3.) more particularly ahydraulic snubber of an improved 'l IDS/{97 DH 188/321 configurationwhich is disposed intermediate 61 bolster l 0 gg f 267/8 R 9 9 308/2 andside frame and which includes a circumferential reservoir outside thepiston stroke area thereby permitting a minimum height snubber for agiven useful [56] References Cited Stroke.

UNITED STATES PATENTS 2,099,240 11/1937 SprOul 267/4 14 Clams, 7 DrawmgFlgures PAIENIEB 191s sum 1 ur 3 OIL LEVEL 1 HYDRAULICALLY SNUBBEDTIiUCK As is known, in the normal travel of railway cars over a railbed,various differences in the vertical profile of the laterally spacedtrucks resulting from such causes as staggered rail joints and superelevation of the outside track on curves gives rise to a tendency oflateral tilting or swaying of the car body. In modern cars with heavyload capacity and a relatively high center of gravity the energyinvolved in the swaying can be a significant part of the total energyavailable in the drawbar force from the locomotive while the forcesapplied to the running or gear of the car become so large at times thata variety of effects may develop such as:

l. Unequal weight distribution which in extreme cases results incomplete unloading of the wheels on one side of the truck to the extentof lifting the unloaded wheels off the rail with a high potential ofderailment;

2. The imposition of extreme stresses on the car body and truck members;and

3. Cumulative damage and misalignment of track,

ties and roadbeds through pounding action.

Various means have been developed to alleviate the above mentionedproblem of swaying including the hydraulic snubbing devices described inU.S. Pat. Application Ser. No. 134,126, filed Apr. 15, l971, andassigned to the same assignee as is this invention. Such applicationillustrates a frequency responsive hydraulic snubber which is disposedintermediate a side frame and bolster and provided with an externalreservoir for hydraulic fluid which cooperates with the snubber cylinderspace to virtually eliminate the dead space or ullage volume normallynecessary within a closed hydraulic cylinder to provide for the volumeof hydraulic liquid which is displaced by the piston rod on the downstroke. By use of such a snubber as described in the aforesaid patentapplication a high energy absorption rate is available at slow carspeeds and large amplitude motions and a low rate of energy absorptionis available at high car speeds and relatively smaller amplitude motionsthereby controlling the frictional temperature rise of the hydraulicsnubbing fluid within an acceptable range. While simultaneouslyproviding an arrangement wherein the snubber is effective oversubstantially the full stroke thereof with substantially zero ullagevolume within the piston cylinder.

The present invention is an improvement over snubbers of a typedescribed in said copending U.S. Patent Application Ser. No. 134,126 andoffers several advantages thereover, for example:

1. By providing a circumferential reservoir outside of the piston strokearea: a more compact snubber assembly is possible; snubber eccentricityis substantially reduced thereby resulting in reduced stress on thesnubber components; and in certain circumstances the decrease in snubbereccentricity alleviates the necessity for a centering plate for thesnubber on the bolster or side frame;

2. The snubber of the present invention when disposed in a spring groupof an existing railway car truck can be positioned with none or onlyminor .alterations to the structure of the adjacent side frame orbolster;

3. The construction of a nodular iron cast body with a steel sleeve forreceiving the piston therewithin alleviates the necessity for a bearingassembly intermediate the adjacent peripheries of the piston stern andthe body bore through which it reciprocates; and

4. The improved snubber configuration requires no closure welds and thesnubber can be readily as sembled and disassembled.

These and other objects and advantages will become more readily apparentupon a reading of the following description and drawings in which:

FIG. I is a cross sectional view of a snubber constructed in accordancewith the principles of the present invention and taken on lines l-l ofFIG. 3;

FIG. 2 is a cross sectional view of the snubber of FIG. 1 taken on line2-2 of FIG. 3;

FIG. 3 is a plan view, partially in section, of the snubber illustratedin FIGS. 1 and 2;

FIG. 4 is a fragmentary side elevational view of a freight car truckincorporating the snubber of this invention;

FIG. 5 is a top plan schematic view of a spring group incorporating thesnubber of this invention;

FIG. 6 is a fragmentary partially sectional and elevational view of thefreight car truck illustrated in FIGS. 4 and 5 and incorporating thesnubber of this invention; and

FIG. 7 is a view similar to FIG. 6 illustrating loaded and unloadedconditions of the freight car incorporating the snubber of thisinvention.

FIG. 4 illustrates a fragmentary portion of a four wheel railway freighttruck, generally illustrated at 10, which comprises a center plate andsuitable side bearings (not shown) cooperating with a bolster 20 tosupport the car body (not shown); spring groups 22 mounted in side frame24 (only one being shown) to support the bolster 20; and suitablyjournaled wheels 26 supporting each side frame 24 and nesting on tracks28. A snubber of the present invention best illustrated in FIGS. 1-3 andgenerally indicated at 30, is shown as being disposed in the springgroup 22.

Inasmuch as the invention herein is primarily directed at snubber 30 andthe balance of the elements set forth hereinabove are well known in theart further description of such elements will not be set forthhereinafter except where necessary to describe snubber 30.

The snubber 30 comprises: a hollow body member 32; a hollow cylindricalsleeve 34 received within snubber 32; a piston assembly 36 axiallyreciprocable within sleeve 34; and a closure and bearing member 37releasably carried by member 32 adjacent the lower end thereof. Bodymember 32 includes; a bearing and sleeve retaining portion 38 adjacentthe lower end of member 32; an upper portion 40; and a radiallyoutwardly expanded reservoir portion 42 located intermediate portions 38and 40. It is to be noted that reservoir portion 42 as illustrated inFIG. 1 includes a sight glass 45 intergral therewith for purposes ofvisual verification of the liquid level within portion 42.

Upper portion 40 of body member 32 includes a circular opening 43therethrough. Opening 43 has a stepped cylindrical periphery surface andincludes: a lower peripheral surface 44 having a diameter thereofsubstantially equal to the outer diameter of sleeve 34; an intermediateperipheral surface 46 having a diameter thereof less than the diameterof portion 44; and an upper piston rod bearing and sealing peripheralsurface 48 having a diameter thereof less than the diameter of portion46. A transversely extending sleeve seating surface 50 is formed at thejuncture of surfaces 46 and 48. In final assembly of snubber 30 theuppermost end of sleeve 34 is firmly seated on seating surface 50.

Portion 38 of body member 32 includes a lower circular opening 52therethrough. As shown opening52 is coaxially aligned with opening 43and has a diameter thereof substantially equal to the outer diameter ofclosure and bearing member 37. The lower surface of member 37 has adownwardly extending convex configuration and the upper surface thereofincludes a central circular depression 54 and a downwardly extendingannular groove 56 therein. Groove 56 is located intermediate theperiphery of depression and the outer periphery of member 37.

In final assembly member 37 is releasably and sealingly received withinopening 52 in any suitable manner. As shown the sealing relationshipbetween member 37 and opening 52 is established by an O-ring 58 disposedin an outwardly extending peripheral groove in opening 52. Thereleasable retention of member 37 within opening 52 is shown as beingaccomplished by means of snap ring 60.

Prior to final assembly, sleeve 34 with piston assembly 36 therewith isreceived within body member 32. The lowermost end of sleeve 34 iscaptively received within the annular groove 56 of member 37 and theupper end thereof engages the annular sleeve seating surface 50.

Piston assembly 36 comprises a piston head 62, and a cylindrical pistonrod 64 suitably secured at the lower end thereof to piston head 62 andextending coaxially upwardly therefrom. Piston head 62 is provided witha central bore 66 therethrough which is in coaxial alignment with ablind central bore 68 in the piston rod 54. In final assembly a spring70 is captively mounted in a compressed condition within the blind bore68 and a plug 72 with a central bore 74 therethrough is threadedlyreceived within bore 66. A ball valve 76 is biased into seatingengagement with bore 74 by spring 70. Assembly 36 additionally includesa ball valve seating member 78 disposed in bore 66 intermediate spring70 and valve 76 to provide a seating and centering means for ball valve76. The piston head 62 is also provided with a plurality ofcircumferentially spaced bores 80 which extend from the bottom surfaceof piston head 62 and open into a plurality of bores 82 which extenddiagonally from bore 66 to the upper surface of piston head 62.

In the position shown in FIG. 2 the bores 80 are sub stantially closedat the lower ends thereof by means of an annular flapper or ring valve84 which covers the lower ends of bores 80 whenever pressure below thepiston head is substantially greater than pressure above the piston head62. The valve 84 is free to move downwardly with respect to the bottomof piston head 52 a limited distance and is prevented from movingfurther in the axial direction by a nut head depending downwardly fromplug 72. Valve 84 includes a plurality of circumferentially spacedopenings 85 therethrough which openly communicate with respective bores80 in piston head 62. A compression spring set 86 is disposed within thesleeve 34 intermediate the piston head 62 and the closure and bearingmember 37 in a manner that the lower end thereof is captively receivedwithin the cylindrical depression 54 and the upper end thereof iscaptively received in a downwardly open annular groove 88 within pistonhead 62. Compression spring set 86 biases piston head 62 upwardly awayfrom member 37.

Body member 32 includes a pair of blind passageways 90 (see FIG. 2)therein having axes parallel to the axis of the piston assembly 36 andextending from the top of reservoir portion 42 downwardly to a pointupwardly adjacent the lower end of portion 42. Plugs 92 are sealinglyreceived within the respective upper ends of passageways 90. An annularfluid reservoir 94 is defined between the outermost periphery of sleeve34 and the innermost periphery of body member reservoir portion 42. Alateral passageway 96 communicates between reservoir 94 and passageways90 adjacent the respective lowermost ends thereof. The open portion ofbody member 32 interiorly of sleeve 34 and adjacent thereto defines thepiston chamber 98. Passageways 90 communicate with chamber 98 by meansof passageways 100. Passageways 100 include a lower portion 102 whichextends transversely inwardly from passageway 90 downwardly adjacent theupper end thereof and a generally vertically extending groove portion104 having the lower end thereof in communication with portion 102. Theupper end of portion 104 extends transversely inwardly upwardly adjacentthe upper end of sleeve 34 and at the inner end thereof openlycommunicates with chamber 98 adjacent the upper end of chamber 98.

Body member 32 includes an annular upwardly facing transverse springseating surface 106 which is formed on the outer periphery thereof atthe intersection of portions 40 and 42. As shown, spring group 22includes a plurality of standard springs 108 and a body spring 110 whichreplaces a standard spring 108 and positions, retains and cooperateswith snubber 30 in a manner as described hereinafter. In position theupper end of spring 110 engages the standard bolster 20 and the lowerend thereof engages the spring seating surface 106 in a manner thatsnubber 30 is biased into position with the lower radially downwardlyextending surface of closure and bearing member 37 engaging the topsurface 112 of the bottom member of the standard side frame 24. It is tobe noted that the structure and passageway configuration of snubber 32permits the captive and frictional retention thereof without anyalteration to the standard bolster 20 and the standard side frame 24 andwithout any direction connection between the snubber 30 and the sideframe 24 and/or bolster 20. Still further the annular configuration ofreservoir 94 reduces snubber eccentricity and alleviates the necessityof a snubber retention or centering plate on the side frame or bolsteras was required in the aforementioned copending US. Patent ApplicationSer. No. 134,126. Furthermore, it is to be noted that the portions ofthe outer periphery of snubber 30 having springs from spring group 22adjacent thereto have a radially inwardly extending arcuateconfiguration thereby providing clearance for the standard springs 108while simultaneously providing maximum utilization of available spacefor the volume of the reservoir 94. In the embodiment of snubber 30illustrated the snubber 30 releases an outside spring in the springgroup 22, thus only the three sides thereof having standard springs 108adjacent thereto have an arcuate configuration; however, it iscontemplated that a snubber constructed according to the principles ofthis invention can be utilized to replace an internal spring in a springgroup 22 and hence all four sides thereof would have a radially inwardlyextending arcuate configuration to provide clearance for the springslaterally adjacent thereto.

When the snubber 30 is assembled with the body spring 110 it extendsbetween the side frame 24 and the bolster 20 as seen in FIG. 6. Also, asseen in FIG. 7 when the snubber 30 is in position in an unloaded car theengaging surface of bolster 20 will be spaced upwardly at line A-A outof engagement with respect to the uppermost extent of piston rod 64.Hence, there would be very little or no action of the snubber 30 even ifthe car should bounce somewhat or rock slightly as it was beingpropelled along the rails. The next horizontal line, namely BB,represents the normal position of the engaging surface of bolster 20with respect to the uppermost extent of piston rod 64 wherein piston rod64 is in engagement with the engaging surface of bolster 20 adjacentthereto. It is seen that at this time the heretofore fully upwardlyextended piston assembly 36 will be forced downwardly into the chamber98.

Snubber 30 is filled by turning it upside down removing member 37 andpouring in a sufficient quantity of suitable hydraulic snubbing fluidsuch that chamber 98 will be completely filled and reservoir 94 will befilled with hydraulic snubber fluid to the level shown FIG. 1 when thesnubber 30 is operational and fully extended. When snubber 30 isoperational and compressed the level of hydraulic snubber fluid inreservoir 94 will be substantially as shown in FIG. 2. It is to be notedthat the level of hydraulic snubber fluid in reservoir 94 when thesnubber is fully extended will be above lateral passageway 96. In otherwords lateral passageway 96 will be continuously below the level ofhydraulic fluid in reservoir 94 regardless of the position of pistonassembly 36.

With snubber 30 filled with hydraulic fluid as described hereinabove theoperational parameters and characteristics are essentially the same asthose described in the aforesaid US. Patent Application Ser. No.134,126. Accordingly, for a detailed description of the operational dataof snubber 30 reference is hereby made to said Application Ser. No.134,126.

An additional feature of the present invention resides in the fact thatbody member 32 is cast as a unitary piece of nodular iron. Accordingly,no welds are necessary in the assembly of snubber 30. The assembly anddisassembly of snubber 30 is accomplished by the mere insertion andremoval of snap ring 30. Furthermore,

casting the body member 32 in nodular iron alleviates the necessity ofhaving a bearing assembly intermediate opening 43 and the piston rod 64which is reciprocable therein.

A preferred embodiment constructed according to the principles of thisinvention having hereinbefore been described it is to be realized thatvariations in the structure embodying the principles of this inventionare possible without departing from the scope of such principles, forexample, the fit between member 37 and opening 52 can be tight therebyproviding for the sealing retention of member 37 within opening 52solely by frictional engagement with no requirement for additionalretention means such as snap ring 60. It is thereby respectfullyrequested that this invention be interpreted only in accordance with thescope of the claims appended hereto.

What is claimed is:

l. A snubber device comprising: a hollow housing; an annular cylindricalmember releasably and rigidly received within said housing; acircumferential fluid reservoir defined by the inner periphery of saidhousing and substantially the entire outer periphery of an upstandingportion of said cylindrical member which is spaced therefrom; a pistonassembly axially reciprocable within said cylindrical member; passagewaymeans communicating between said reservoir and the interior of saidcylindrical member adjacent the uppermost portion of said cylindricalmember; said interior of said cylindrical member, said passageway meansand said res ervoir defining a closed hydraulic system for retaining ahydraulic fluid therein; and said passageway means being incommunication with said reservoir below the operating level of thehydraulic fluid in said reservoir.

2. A snubber device as specified in claim 1 wherein said passagewaymeans is formed within the wall of said housing.

3. A snubber device as specified in claim 2 wherein a portion of saidpassageway means comprises a radially inwardly and vertically extendinggroove within the wall of said housing.

4. A snubber device as specified in claim 3 wherein a portion of theouter periphery of said cylindrical member is adjacent said groove.

5. A snubber device as specified in claim 1 including means disposedwithin said housing intermediate the lower end thereof and said pistonassembly which biases said piston assembly upwardly.

6. A snubber device as specified in claim 1 wherein the lower end ofsaid housing sealingly receives a housing closure member therein.

7. A snubber device as specified in claim 6 wherein said closure memberincludes an upwardly open annular seating groove therein, said seatinggroove being adapted to seat the lower end portion of said cylindricalmember therein.

8. A snubber device as specified in claim 1 wherein said housing closuremember is solely frictionally retained within the lower end of saidhousing.

9. A snubber device as specified in claim 1 wherein said piston assemblycomprises a piston head and a piston rod and said housing includes aninner peripheral seal adjacent the upper end thereof, and saidperipheral seal maintains the hydraulic fluid within said housing bymaintaining a seal between said housing and said piston rod which isreciprocal through the upper end of said housing.

10. A snubber device as specified in claim 1 which is adapted to beinterposed in a spring group intermediate a bolster member and a sideframe member and said housing includes a peripheral portion concavedinwardly to provide clearance for the springs of such a spring groupwhich are adjacent thereto.

11. In a railway truck assembly in which a fluid snubber assembly havinga pair of elongated sections telescopically movable with respect to eachother along a longitudinal axis thereof is interposed in the springgroup intermediate a bolster member and a side frame member, theimprovement comprising: said snubber assembly including a radiallyoutwardly and circumferentially extending fluid reservoir; and saidreservoir including at least one peripheral portion which is concavedradially inwardly to provide clearance for the springs of said springgroup which are transversely adjacent thereto.

way truck assembly intermediate a bolster member and a side framemember, the improvement comprising: said snubber assembly including aradially outwardly and circumferentially extending fluid reservoir; andsaid reservoir including at least one peripheral portion which isconcaved radially inwardly to provide clearance for the springs of sucha spring group which are transversely adjacent thereto when said snubberassembly is interposed in such a spring group.

1. A snubber device comprising: a hollow housing; an annular cylindricalmember releasably and rigidly received within said housing; acircumferential fluid reservoir defined by the inner periphery of saidhousing and substantially the entire outer periphery of an upstandingportion of said cylindrical member which is spaced therefrom; a pistonassembly axially reciprocable within said cylindrical member; passagewaymeans communicating between said reservoir and the interior of saidcylindrical member adjacent the uppermost portion of said cylindricalmember; said interior of said cylindrical member, said passageway meansand said reservoir defining a closed hydraulic system for retaining ahydraulic fluid therein; and said passageway means being incommunication with said reservoir below the operating level of thehydraulic fluid in said reservoir.
 2. A snubber device as specified inclaim 1 wherein said passageway means is formed within the wall of saidhousing.
 3. A snubber device as specified in claim 2 wherein a portionof said passageway means comprises a radially inwardly and verticallyextending groove within the wall of said housing.
 4. A snubber device asspecified in claim 3 wherein a portion of the outer periphery of saidcylindrical member is adjacent said groove.
 5. A snubber device asspecified in claim 1 including means disposed within said housingintermediate the lower end thereof and said piston assembly which biasessaid piston assembly upwardly.
 6. A snubber device as specified in claim1 wherein the lower end of said housing sealingly receives a housingclosure member therein.
 7. A snubber device as specified in claim 6wherein said closure member includes an upwardly open annular seatinggroove therein, said seating groove being adapted to seat the lower endportion of said cylindrical member therein.
 8. A snubber device asspecified in claim 1 wherein said housing closure member is solelyfrictionally retained within the lower end of said housing.
 9. A snubberdevice as specified in claim 1 wherein said piston assembly comprises apiston head and a piston rod and said housing includes an innerperipheral seal adjacent the upper end thereof, and said peripheral sealmaintains the hydraulic fluid within said housing by maintaining a sealbetween said housing and said piston rod which is reciprocal through theupper end of said housing.
 10. A snubber device as specified in claim 1which is adapted to be interposed in a spring group intermediate abolster member and a side frame member and said housing includes aperipheral portion concaved inwardly to provide clearance for thesprings of such a spring group which are adjacent thereto.
 11. In arailway truck assembly in which a fluid snubber assembly having a pairof elongated sections telescopically movable with respect to each otheralong a longitudinal axis thereof is interposed in the spring groupintermediate a bolster member and a side frame member, the improvementcomprising: said snubber assembly including a radially outwardly andcircumferentially extending fluid reservoir; and said reservoirincluding at least one peripheral portion which is concaved radiallyinwardly to provide clearance for the springs of said spring group whichare transversely adjacent thereto.
 12. A railway truck assembly asspecified in claim 11 wherein said reservoir has a generally annularconfiguration.
 13. A railway truck assembly as specified in claim 12wherein said snubber assembly is a hydraulic snubber assembly.
 14. In afluid snubber assembly having a pair of elongated sectionstelescopically movable with respect to each other along a longitudinalaxis thereof and adapted to be interposed in the spring group of arailway truck assembly intermediate a bolster member and a side framemember, the improvement comprising: said snubber assembly including aradially outwardly and circumferentially extending fluid reservoir; andsaid reservoir including at least one peripheral portion which isconcaved radially inwardly to provide clearance for the springs of sucha spring group which are transversely adjacent thereto when said snubberassembly is interposed in such a spring group.